Polyvinylidene Fluoride
Introduction
Polyvinylidene fluoride (PVDF) is a highly non-reactive and pure thermoplastic that is used in applications requiring the highest purity, as well as resistance to solvents, acids and hydrocarbons. It is a specialty plastic used in applications requiring the highest purity, as well as resistance to solvents, acids and hydrocarbons. Compared to other fluoropolymers, it has an easier melt process because of its relatively low melting point of around 177°C.
History
The polymer was discovered in 1969 by Dr. Heijji Kawai, working at the Pennwalt Corporation. It was commercialized in 1972 after the company developed a process for its polymerization.
Properties
PVDF is a tough engineering thermoplastic with a balance of physical and chemical properties that qualify it for high performance service in a wide range of applications. It is resistant to most chemicals and solvents, has excellent wear and abrasion resistance, good mechanical strength and toughness, and excellent thermal stability. It also has a high dielectric strength and is not affected by prolonged exposure to sunlight.
Structure
PVDF is a polymer composed of a chain of vinylidene fluoride (VDF) monomers. It is a semi-crystalline polymer that can exist in several different crystalline forms depending on the processing conditions. It has a high degree of crystallinity, and it is this crystalline structure that provides the polymer with its unique properties.
Applications
PVDF is used in a wide range of applications. These include, but are not limited to, the following:
- Chemical processing: PVDF is used in piping, tubing, vessel linings, tower packing, and heat exchangers for its resistance to corrosive chemicals and high temperatures.
- Electronics: PVDF is used in wire insulation, semiconductor fabrication, and lithium-ion batteries due to its high dielectric constant and high thermal stability.
- Medical: PVDF is used in catheters, tubing for dialysis, and surgical sutures for its biocompatibility and sterilizability.
- Oil and gas: PVDF is used in tubing, pipes, and liners for its resistance to hydrocarbons and excellent mechanical properties.
Manufacturing Process
The manufacturing process of PVDF involves the polymerization of vinylidene fluoride. The process can be carried out in several ways, including suspension polymerization, emulsion polymerization, and bulk polymerization. The choice of polymerization method depends on the desired properties of the final product.
Environmental Impact
PVDF is a stable polymer that does not degrade under normal environmental conditions. It is resistant to UV radiation and does not leach any harmful substances into the environment. However, like all plastics, it does not biodegrade and should be properly disposed of or recycled to minimize its environmental impact.